Laminated metal body



LAMINATED METAL BODY Filed Dec. 8, 1936 Inventor- Ernst, Br-Uche HisAttorney.

Patented Apr. 4, 193a um'rso ra-reef PATENT emee amazes LAMINATEDiur'ru. BODY Ernst serene.

assign Berlin-Belnickendorf', or to General Electric Company, porationof New York plication'necember 8, 19 6, Serial No. 114,831-

In Germany Decem 48,

s elm (o1. sir-var The present invention relates to laminated- I metalbodies and to a method of fabricating such bodies.

It is a particular object of the invention to 5 provide a laminatedstructure of such nature that its cross-sectional surface may beutilized as an optical 'difiraction grating. It is recognized, however,that metals fabricated in accordance 'with the method described in thefollowing are 1 capable of other uses and it is intended to insistalternately'oi a chemically inert material and a material which iscapable oi being-attached chemically. With this condition fulfilled, agiven cross-section or the composite body may be cut.

and polished and afterwards etched. By this last step, the layers whichare less chemically resistant manifest themselves as fine grooves whichrepresent a line grating with a large number oi lines per millimeter.

One arrangement by which the invention may 35 be suitably carried out isillustrated in the single figure of the drawing and may be described asfollows: On a horizontal metal disk I which is rotatably mounted on itsaxis two vapor jet crucibles 3 and 4 are secured in diametricallyopposite positions. One crucible or vapor source has a jet 5 whichdischarges gold vapor, for ex-- ample, and the other a jet 6 whichdischarges a less inert material such as silver vapor. Above the disk,which may be rotated at a desired speed 4 around its vertical axis, ametal plate 1 adapted.

to condense the vapor is so suspended that the crucibles successivelyand repetitively swinging in a reentrant path past the surface of theplate create at each passing a very thin deposit of 50 gold of silver asthe case may be.

proportioning the rate of vapor discharge, the distance between thecrucibles and the plate, and the speed of rotation, of the disk, it ispossible to control the thickness of the individual stratified 68layers. It is entirely practicable to give the istics entirely differentlayers a thicknesscomparablewith the wave length of light so that asmany as 1000 to 2000 millimeter will be deposited.

accumulated laminations have say, 2 millimeterathe.

layers per As soon as the attained a thickness of,

composite body is cut vertically together with the supporting plate. Thepolished and treated in the surface is free of all polished surface isthen etched chemically,

cut section is next a suitable manner until distortions. If the theattack on the silver will be more'pronounced than that on the gold, sothat fine grooves or furrows are created. These grooves may be used forpurposes of light difl'ractlon in a manner well understood by thoseskilled inthe optical arts. It

should be pointed out that a grating produced in accordance with theforegoing method is especially suited for the spectral difiraction ofelec tronlc rays in which it is desired to separate electrons oi agivenvelocity from those. of differing velocities.

The cross-section oi a stratifled type above descrlbed may be preparedas an optical grating by means other than by etching. For-example, iithe cross-section is ground and polished to a concave form, ment betweenthe exposed edges of the various laminations will be suficient toproduce diflraction eflects. Furthermore, instead of gold and silver asspecified above, it may in certain cases be desirable to use othermaterials in the prepabody of the the relative .displaceration of thelaminated structure. For'example,

it may be advantageous in certain instances to use alternate layers of ametal and an insulator such as a salt. Such a combination may comprise,for example, layers of a salt of ammonium (e. g., NHQCD alternated withlayers of silver.

While particularly applicable thereto;v the,

method described in the foregoing is not necessarlly limited totheproduction of optical gratings. For example, it is possible to producestructural members having great strength and other unusual physicalproperties by the use of superimposed laminations of extreme thinness asspecified in the foregoing. By using st tural metals such as iron andalumin for" ample, instead of gold and silver, composite metal bodiesmay be obtained having character,-

from those which would result from direct alloying of these materials;Indeed, the type of fabrication outlined in the foregoing may beapplicable in cases where alloying of the selected materials isimpossible.

Iaiminthe appendedclaimBtocov-er 88 and modes of application of theinvention which come within the true spirit and scope of the foregoingdisclosure.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1. The processoi' depositing alternate layers of I different solidvaporizable materials on asurrace adapted to condense such materialswhichcomprises providing separate sources of the materials, heating suchsources to efl'ect vaporization of the materials, and moving the sourcesalong a reentrant path while continuing such vaporization to bring thesources successively and repetitively into proximity to said surface. a

'2. The process of forming composite coatings by evaporation induced'byheat which comprises to a suri'ace adapted to condense the said va- 1 0porized materials.

-. ERNST BRUCHE.

